Question

If the electric resistance of a wire is R= ((pl)/A), where p is the specific resistance of the material of the wire, l is the length of the wire and A is the area of a cross-section. If specific resistance and cross-sectional area are fixed, the rate of change of R with respect to length is a)l/A b)pl c)-(pl/A^2) d)-(2pl/A^2) e) p/A